Margin bar for printing cylinders



1937- H. A. w.-wooD I MA'RGTN BAR FOR PRTNTTNG CYLTNDFRS Original Filed March 21, 1934 4 Sheets-Sheet l H. A. W. WOOD Nov. 23, 1937.

MARGTN BAR FOR FRTNTTNG CYLINDERS Original Filed March 21, 1954 4 Sheets-Sheet 2 Nov. 23, 1937. H. A. w. WOOD MARGIN BAR FOR PRINTING CYLINDERS Original Filed March 21, 1934 4 Sheets-Sheet 3 KW M mmiiiilililiiiiiiii Nov. 23, 1937. H, w WOOD 2,100,208

MARGIN BAR FOR PRTNITN'G CYLINDERS Original Filed March 21, 1934 4 Sheets-Sheet 4 IAWV/EOZ Patented Nov. 23, 1937 UNITED STATES PATENT OFFICE MARGIN BAR FOR PRINTING CYLINDERS Application March 21, 1934, Serial No. 716,560 Renewed May 4, 1937 6 Claims.

The principal objects of this invention are to provide an arrangement for a margin bar of such a nature that if the plates are not manufactured the same length tolerances are permitted so that the margin bar follows the plate and performs its function of holding the straight edge of the plate against the cylinder; to provide means whereby the plate can grow on the cylinder, as it passes in-and out of the impression a large number of times, without buckling the plate and causing trouble and without impairing the margin bars function of holding down the straight edges of the plates; to provide for some flexibility in the marginbar so that, if adjacent plates on opposite l5 sides of the bar are of difi'erent heights on the ledge, there will be compensation so that the bar may press against both plates despite small variations in the heights of the ledges; to provide a margin bar which is movable longitudinally to clamp and releasethe straight edges of the plate; to provide a margin bar so arranged that the longitudinal motion is accomplished automatically when the plates are clamped and unclamped; to provide means for accommodating'plates of varying length without impairing the efiectiveness of the means for holding down their straight edges, and to provide means whereby the tendency of the trailing edge of the plate to crowd against'the margin bar while the leading edge works away from it will be avoided and both edges will be securely held against the cylinder.

Other objects and advantages of the invention will appear hereinafter.

35 Reference is to be had to the accompanying drawings, in which- Fig. 1 is a diagrammatic view of the end of a printing press of the type on which this invention is used;

Fig. 2 is a transverse sectional view of the plate cylinder showing .a longitudinal movable split margin. bar which iscompressible circumferentially of the cylinder;

Fig. 3 is an elevation taken in the direction of 45 the arrow 3 in Fig. '2 and showing one pair of margin bars;

Fig. 4 is a similar view showing half the length of the cylinder;

Fig. 5 is a sectional view of the same on the 50 line 5-5 of Fig. 4;

Fig. 6 is a similar view with the end clamp drawn away and both plates free;

Fig. 7 is a view similar to Fig. 4 of a modified v form. of this invention in which the margin bars 55 are'fixed longitudinally but movable circumferentially to care for variations in the circumferential length of the printing plates and where the margin bars act in different directions and are offset from each other;

Fig. 8 is a sectional view on the line 8-8 5 of Fig. 7;

Fig. 9 is a sectional view on the line 9-9 of Fig. 7;

Fig. 10 is a sectional view similar to Fig. 8 showing the position the margin bars assume when 10 there are no plates on the cylinder;

Fig, 11 is a view similar to Fig. 4 of another form comprising a movable margin bar carrying a pivoted operating end; 1

Fig. 12 is a sectional view on the line l2--l2 of Fig. 11;

Fig. 13 is a longitudinal sectional view on the line l3-|3 of Fig. 11, and

Fig. 14 is a cross sectional end view of the third form shown, similar to Fig. 12, showing the position the parts assume as the plate cylinder rotates.

Fig, 1 is presented to show a printing press of the general character on which this invention is useful. It shows only the well known features, namely the impression cylinder I, plate cylinder 2, form rollers 3, ink drum 4, rubber rolls .5, pickup roll 6 and fountain roll 1. Such a press is used usually in newspaper work. The plate cylinder 2 carries the usual end clamps 8, stationary center ring 9 and movable center clips ID. The end clamps 8 are slidable in key slots II on the cylinder 2 in the usual manner.

A T-slot I2 is provided in the cylinder 2 and on its bottom or floor tapers toward the axis of 3 the cylinder as it progresses from its outer edge toward the middle of the cylinder. Margin bars l3 and M are provided to fit in the T-slot I2 in cooperation with an operating rod IS. The two margin bars shown in Figs. 2 and 3 perform the function heretofore performed by a single margin bar and also other functions, as will appear.

The space usually occupied by a margin bar is filled by these two margin bars I3 and I4 and they are so located in the T-slot that they sub- 4 stantially fill the same. Springs [6 are located between the two margin bars to hold them apart. The margin bars are pushed in and out by moving them longitudinallyalong the inclined surface of the bottom of the T-slot.

Bearings I1 and [8 are secured in the cylinder 2 and penetrated by the rod 15 to provide a backing for springs l9 and 20. The outer ends of the springs I9 and 20 respectively bear, through the washers 2!, against the margin bars l3 and '5 I4 in one case and 22 and 23 in the other. These margin bars 22 and 23 are formed the same as the margin bars l3 and I4 and are located in a position to engage a different plate. It is customary to clamp two plates with a single set of end clamps and a set of margin bars is provided for each plate. Lock nuts 24 and 25 serve to move the margin bars l3 and I4, 22 and 23 respectively to the right, when the plates are unclamped, as shown in Fig. 6.

On account of the longitudinal taper of the fioor of the slot [2 these margin bars lift away from the cylinder and release the pressure which has been exerted against the ledges 26 of the plates P when the plates are unclamped. From Fig. 2 it is apparent that any slight irregularity in the circumferential length of the plate P will be taken care of by the springs I6 between the margin bars. This will be done without any interference with the holding down of the plate P by the operation of the margin bars on the ledges 25.

It will be seen, therefore, that this form of the invention includes a device which is movable longitudinally to clamp and release the straight edges of the plate and that this device is so placed that this is done automatically when the plates are clamped and unclamped. Means is provided for accommodating plates of various lengths without impairing the effectiveness of the means for holding down the straight edges of the plates.

In the form shown in Figs. 7 to 10 inclusive alternating margin bars 21, 28 and 29 are pivotally mounted on a shaft 30 which is secured in the cylinder 2 by brackets 31 and 32. The two margin bars 21 and 28 tend to rotate in a clockwise direction while the center margin bar 29 tends to rotate in a counterclockwise direction. This is accomplished by the action of springs 33 wound on the shaft 35 and having their opposite ends projecting into the margin bars. These bars are not movable longitudinally but, by the spring arrangements, permit variation in the circumferential length of the plate P and still perform the function of holding the straight edges of the plate down by action of the margin bars against the ledges 25.

Figs. 11 to 14 show still another modification in which a T-slot 34 similar to the T-slot l2, shown in Fig. 2, provides a mounting for a bar 35. Any longitudinal motion of this bar along the T-slot 34 will cause the bar 35 to move toward or away from the center of the cylinder because the floor of the T-slot is slanted, as was the case in the first form of this invention described.

The margin bar 35 is pivotally attached to the bar 35 by a longitudinal rod 31. The bar 35 is moved by means substantially the same as described in connection with the first form of the invention. It comprises a member 38 secured to a rod 39 by lock nuts 40. The rod carries a spring 4|, one end of which projects against a bracket 44 fastened to the cylinder 2. The other end of the spring bears against the bar 35. A collar 43 on the end of the rod 39 serves to move the bar 35 to the right automatically when the plates are unclamped. This motion elevates the margin bar 36 from the ledges 26 on the plates P and thereby releases them. When the plates are clamped the spring 4| forces the bar 35 to the left thereby bringing the margin bar 36 firmly down against the ledges 26.

It is well known that, as the plate cylinder rotates in the direction of the arrow shown in Fig. 14, the trailing edge of the plate necessarily bears firmly against the margin bar. This tends I against the cylinder.

to make the trailing edge of the plate crowd against the margin bar while the leading edge works away from it, as shown in Fig. 14.

The object of the construction shown in these figures is to provide means whereby, regardless of the crowding of the plate against the margin bars on one side and moving away on the other, the pivoted bar 26 rests against both ledges and securely holds the straight edge of the plate Fig. 14 shows this condition.

It will be seen therefore that in all these forms a yieldable construction is shown in the margin bar, or in the relation between two margin bars, so that, if the plates are not manufactured exactly the same length, the margin bar will hold the plate and perform its function perfectly. Also the plate can grow from passing in and out of the impression and the margin bar will yield to it so that no buckling will take place and there will be no impairment of the efiiciency of the margin bar in holding down the plate. Furthermore, if adjacent plates on opposite sides of the bar are different heights on the ledge, the bar is flexible enough to cooperate with them to compensate' for any difference. 7

Having described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed otherwise than as set forth in the claims but what I claim is:-

l. The combination with a printing plate cylinder having a longitudinal groove, of a pair of margin bars located in said groove and projecting beyond the surface of the cylinder, each margin bar having a projection for engaging the ledge of a printing plate, said margin bars being movable circumferentially to properly hold down the ledges of two plates on the cylinder located on opposite sides of the two margin bars.

2. The combination with a printing plate cylinder having a T-shaped longitudinal slot provided with a floor slanting longitudinally, of two margin bars located in said slot against said floor and projecting beyond the surface of the cylinder, each provided with means for engaging the ledge of one plate on the cylinder and means for moving the margin bars along the inclined fioor to raise and lower them.

3. The combination with a printing plate cylinder having a longitudinal T-shaped slot with a slanting bottom, of a pair of margin bars located in the slot against said bottom, one having a flange projecting from its outer end for engaging and holding down the ledge of an adjacent printing plate, a rod extending longitudinally of the margin bars and having means for engaging the margin bars to draw them up the incline of said bottom, and an end clamp for the plate having means for engaging said rod and operating it when the end clamp is drawn back to release the plates.

4. The combination with a printing plate cylinder having a longitudinal slot, of a series of margin bars alternating with each other and located in said slot and yielding means for forcing every alternate bar in one direction circumferentially and the others in the opposite direction, said bars each having a flange for engaging the holding ledge of an adjacent plate. 1

5. The combination with a printing plate cylinder having a longitudinal slot, of a rod located in the slot, a series of margin bars pivotally mounted on said rod, each bar having a projection for engaging and holding the ledge of an adjacent plate, said projections extending in opposite direc-' 16 tions on alternate bars, and coil springs wound plates on opposite sides of the bar, each part beon the rod and each engaging two adjacent bars ing movable circumferentially on a printing plate for swinging the two adjacent bars in opposite cylinder, and means for yieldingly pushing each directions. part oppositively toward the ledge of the plate 6. A margin bar made up of two separate parts which it is designed to clamp.

for clamping the straight ledges of two adjacent HENRY A. WISE WOOD. 

